# -*- coding: binary -*-

module Msf

###
#
# This module exposes methods for querying a remote DNS service
#
###
module Exploit::Remote::DNS
module Enumeration

  include Client
  include Msf::Auxiliary::Report

  def initialize(info = {})
    super

    register_advanced_options(
      [
        OptBool.new('DnsNote', [false, 'Save all DNS results as notes', true]),
        OptInt.new('DnsClientUdpTimeout', [true, 'Number of seconds to wait for a response to a UDP query', 8])
      ]
    )
  end

  alias dns_query query

  def setup_resolver
    dns_resolver = super
    dns_resolver.udp_timeout = datastore['DnsClientUdpTimeout']
    @dns_resolver = dns_resolver
  end

  def dns_axfr(domain)
    if datastore['NS'].blank?
      nameservers = dns_get_ns(domain)
      nameservers.map! { |ns| Rex::Socket.dotted_ip?(ns) ? ns : dns_get_a(ns, 'DNS AXFR records') }
      nameservers.compact!
      nameservers.flatten!
    else
      nameservers = process_nameservers
    end
    nameservers.uniq!

    return if nameservers.blank?
    records = []
    nameservers.each do |nameserver|
      print_status("Attempting DNS AXFR for #{domain} from #{nameserver}")
      dns = setup_resolver

      begin
        dns.nameservers = [ nameserver ]
        zone = dns.axfr(domain)

      # Original set of exceptions which were deliberately caught but were missing some
      # situations. Leaving these in as they may want to be treated differently
      # to other, maybe more generic, exceptions.
      rescue ResolverArgumentError, Errno::ECONNREFUSED, Errno::ECONNRESET, Errno::ETIMEDOUT, ::NoResponseError, ::Timeout::Error => e
        print_error("Query #{domain} DNS AXFR - exception: #{e}")
        next
      rescue => e
        print_error("Query #{domain} DNS AXFR - unknown exception: #{e}")
        next
      end

      if zone.blank?
        print_status("Query #{domain} DNS AXFR - no results were received")
        next
      end

      records += zone
      print_good("#{domain} Zone Transfer:")
      print_line(zone.map(&:inspect).join)
    end
    return if records.blank?
    records
  end

  def dns_bruteforce(domain, wordlist, threads)
    return if wordlist.blank?
    threads = 1 if threads <= 0

    queue = []
    File.foreach(wordlist) do |line|
      queue << "#{line.chomp}.#{domain}"
    end

    records = []
    until queue.empty?
      t = []
      threads = 1 if threads <= 0

      if queue.length < threads
        # work around issue where threads not created as the queue isn't large enough
        threads = queue.length
      end

      begin
        1.upto(threads) do
          t << framework.threads.spawn("Module(#{refname})", false, queue.shift) do |test_current|
            Thread.current.kill unless test_current
            a = dns_get_a(test_current, 'DNS bruteforce records', true)
            records |= a if a
          end
        end
        t.map(&:join)

      rescue ::Timeout::Error
      ensure
        t.each { |x| x.kill rescue nil }
      end
    end
    records
  end

  def dns_get_a(domain, type='DNS A records', displayed=false)
    resp = dns_query(domain, 'A')
    return if resp.blank? || resp.answer.blank?

    records = []
    resp.answer.each do |r|
      next unless r.class == Dnsruby::RR::IN::A
      records << r.address.to_s
      print_good("#{domain} A: #{r.address} ") if displayed
    end
    return if records.blank?
    dns_note(domain, type, records) if datastore['DnsNote']
    records
  end

  def dns_get_cname(domain)
    print_status("Querying DNS CNAME records for #{domain}")
    resp = dns_query(domain, 'CNAME')
    return if resp.blank? || resp.answer.blank?

    records = []
    resp.answer.each do |r|
      next unless r.class == Dnsruby::RR::IN::CNAME
      records << r.cname.to_s
      print_good("#{domain} CNAME: #{r.cname}")
    end
    return if records.blank?
    dns_note(domain, 'DNS CNAME records', records) if datastore['DnsNote']
    records
  end

  def dns_get_mx(domain)
    print_status("Querying DNS MX records for #{domain}")
    begin
      resp = dns_query(domain, 'MX')
      return if resp.blank? || resp.answer.blank?

      records = []
      resp.answer.each do |r|
        next unless r.class == Dnsruby::RR::IN::MX
        records << r.exchange.to_s
        print_good("#{domain} MX: #{r.exchange}")
      end
    rescue SocketError => e
      print_error("Query #{domain} DNS MX - exception: #{e}")
    ensure
      return if records.blank?
      dns_note(domain, 'DNS MX records', records) if datastore['DnsNote']
      records
    end
  end

  def dns_get_ns(domain)
    print_status("Querying DNS NS records for #{domain}")
    resp = dns_query(domain, 'NS')
    return if resp.blank? || resp.answer.blank?

    records = []
    resp.answer.each do |r|
      next unless r.class == Dnsruby::RR::IN::NS
      records << r.nsdname.to_s
      print_good("#{domain} NS: #{r.nsdname}")
    end
    return if records.blank?
    dns_note(domain, 'DNS NS records', records) if datastore['DnsNote']
    records
  end

  def dns_get_ptr(ip)
    resp = dns_query(ip, 'PTR')
    return if resp.blank? || resp.answer.blank?

    records = []
    resp.answer.each do |r|
      next unless r.class == Dnsruby::RR::IN::PTR
      records << r.rdata.to_s
      print_good("#{ip}: PTR: #{r.rdata} ")
    end
    return if records.blank?
    dns_note(ip, 'DNS PTR records', records) if datastore['DnsNote']
    records
  end

  def dns_get_soa(domain)
    print_status("Querying DNS SOA records for #{domain}")
    resp = dns_query(domain, 'SOA')
    return if resp.blank? || resp.answer.blank?

    records = []
    resp.answer.each do |r|
      next unless r.class == Dnsruby::RR::IN::SOA
      records << r.mname.to_s
      print_good("#{domain} SOA: #{r.mname}")
    end
    return if records.blank?
    dns_note(domain, 'DNS SOA records', records) if datastore['DnsNote']
    records
  end

  def dns_get_srv(domain)
    print_status("Querying DNS SRV records for #{domain}")
    srv_protos = %w(tcp udp tls)
    srv_record_types = %w(
      gc kerberos ldap test sips sip aix finger ftp http
      nntp telnet whois h323cs h323be h323ls sipinternal sipinternaltls
      sipfederationtls jabber jabber-client jabber-server xmpp-server xmpp-client
      imap certificates crls pgpkeys pgprevokations cmp svcp crl oscp pkixrep
      smtp hkp hkps)

    srv_records_data = []
    srv_record_types.each do |srv_record_type|
      srv_protos.each do |srv_proto|
        srv_record = "_#{srv_record_type}._#{srv_proto}.#{domain}"
        resp = dns_query(srv_record, 'SRV')
        next if resp.blank? || resp.answer.blank?
        srv_record_data = []
        resp.answer.each do |r|
          next if r.class == Dnsruby::RR::IN::CNAME
          data = {
            host: r.name.to_s,
            port: r.port,
            priority: r.priority
          }
          print_good("#{srv_record} SRV: #{data}")
          srv_record_data << data
        end
        if datastore['DnsNote']
          srv_records_data << {
            srv_record => srv_record_data
          }
          report_note(
            type: srv_record,
            data: srv_record_data
          )
        end
      end
    end
    return if srv_records_data.empty?
  end

  # https://data.iana.org/TLD/
  def dns_get_tld(domain)
    print_status("Querying DNS TLD records for #{domain}")
    domain_ = domain.split('.')
    domain_.pop
    domain_ = domain_.join('.')

    tlds = [
      'com', 'org', 'net', 'edu', 'mil', 'gov', 'uk', 'af', 'al', 'dz',
      'as', 'ad', 'ao', 'ai', 'aq', 'ag', 'ar', 'am', 'aw', 'ac', 'au',
      'at', 'az', 'bs', 'bh', 'bd', 'bb', 'by', 'be', 'bz', 'bj', 'bm',
      'bt', 'bo', 'ba', 'bw', 'bv', 'br', 'io', 'bn', 'bg', 'bf', 'bi',
      'kh', 'cm', 'ca', 'cv', 'ky', 'cf', 'td', 'cl', 'cn', 'cx', 'cc',
      'co', 'km', 'cd', 'cg', 'ck', 'cr', 'ci', 'hr', 'cu', 'cy', 'cz',
      'dk', 'dj', 'dm', 'do', 'tp', 'ec', 'eg', 'sv', 'gq', 'er', 'ee',
      'et', 'fk', 'fo', 'fj', 'fi', 'fr', 'gf', 'pf', 'tf', 'ga', 'gm',
      'ge', 'de', 'gh', 'gi', 'gr', 'gl', 'gd', 'gp', 'gu', 'gt', 'gg',
      'gn', 'gw', 'gy', 'ht', 'hm', 'va', 'hn', 'hk', 'hu', 'is', 'in',
      'id', 'ir', 'iq', 'ie', 'im', 'il', 'it', 'jm', 'jp', 'je', 'jo',
      'kz', 'ke', 'ki', 'kp', 'kr', 'kw', 'kg', 'la', 'lv', 'lb', 'ls',
      'lr', 'ly', 'li', 'lt', 'lu', 'mo', 'mk', 'mg', 'mw', 'my', 'mv',
      'ml', 'mt', 'mh', 'mq', 'mr', 'mu', 'yt', 'mx', 'fm', 'md', 'mc',
      'mn', 'ms', 'ma', 'mz', 'mm', 'na', 'nr', 'np', 'nl', 'an', 'nc',
      'nz', 'ni', 'ne', 'ng', 'nu', 'nf', 'mp', 'no', 'om', 'pk', 'pw',
      'pa', 'pg', 'py', 'pe', 'ph', 'pn', 'pl', 'pt', 'pr', 'qa', 're',
      'ro', 'ru', 'rw', 'kn', 'lc', 'vc', 'ws', 'sm', 'st', 'sa', 'sn',
      'sc', 'sl', 'sg', 'sk', 'si', 'sb', 'so', 'za', 'gz', 'es', 'lk',
      'sh', 'pm', 'sd', 'sr', 'sj', 'sz', 'se', 'ch', 'sy', 'tw', 'tj',
      'tz', 'th', 'tg', 'tk', 'to', 'tt', 'tn', 'tr', 'tm', 'tc', 'tv',
      'ug', 'ua', 'ae', 'gb', 'us', 'um', 'uy', 'uz', 'vu', 've', 'vn',
      'vg', 'vi', 'wf', 'eh', 'ye', 'yu', 'za', 'zr', 'zm', 'zw', 'int',
      'gs', 'info', 'biz', 'su', 'name', 'coop', 'aero'
    ]

    records = []
    begin
      tlds.each do |tld|
        tldr = dns_get_a("#{domain_}.#{tld}", 'DNS TLD records')
        next if tldr.nil?
        records |= tldr
        print_good("#{domain_}.#{tld}: TLD: #{tldr.join(',')}")
      end
    rescue ArgumentError => e
      print_error("Query #{domain} DNS TLD - exception: #{e}")
    ensure
      records
    end
  end

  def dns_get_txt(domain)
    print_status("Querying DNS TXT records for #{domain}")
    resp = dns_query(domain, 'TXT')
    return if resp.blank? || resp.answer.blank?

    records = []
    resp.answer.each do |r|
      next unless r.class == Dnsruby::RR::IN::TXT
      txt = r.strings.join(' ')
      records << txt
      print_good("#{domain} TXT: #{txt}")
    end
    return if records.blank?
    dns_note(domain, 'DNS TXT records', records) if datastore['DnsNote']
    records
  end

  def dns_note(target, type, records)
    data = { 'target' => target, 'records' => records }
    report_note(host: target, sname: 'dns', type: type, data: data, update: :unique_data)
  end

  def dns_reverse(cidr, threads)
    unless cidr
      print_error 'ENUM_RVL enabled, but no IPRANGE specified'
      return
    end

    iplst = []
    ipadd = Rex::Socket::RangeWalker.new(cidr)
    numip = ipadd.num_ips
    while iplst.length < numip
      ipa = ipadd.next_ip
      break unless ipa
      iplst << ipa
    end

    records = []
    while !iplst.nil? && !iplst.empty?
      t = []
      threads = 1 if threads <= 0
      begin
        1.upto(threads) do
          t << framework.threads.spawn("Module(#{refname})", false, iplst.shift) do |ip_text|
            next if ip_text.nil?
            a = dns_get_ptr(ip_text)
            records |= a if a
          end
        end
        t.map(&:join)

      rescue ::Timeout::Error
      ensure
        t.each { |x| x.kill rescue nil }
      end
    end
    records
  end

  def dns_wildcard_enabled?(domain)
    records = dns_get_a("#{Rex::Text.rand_text_alpha(16)}.#{domain}", 'DNS wildcard records')
    if records.blank?
      false
    else
      print_warning('dns wildcard is enable OR fake dns server')
      true
    end
  end

end
end
end
